Benzanthronyl compounds



United States Patent 7 Claims. (Cl. 260-364) This invention relates to a process of preparing substantially pure fi-Bz-l-diaminobenzanthrone and to intermediates therefor and to azo dyes obtainable from diaminobenzanthrone.

Deep shades are difiicult to obtain in azo dyes. Often it is necessary to make complicated trisazo and tetrakisazo dyes in order to obtain some deep shades. It is very desirable in azo dyestuffs to obtain a diazo intermediate which will give a wide range of shades, and, especially, one which will give a wide range of deep shades, in the form of monoazo or, at the most, disazo dyes, since the extra coupling steps, as well as the extra materials may often be quite costly.

I have found a process for preparing Bz-l,6-diaminobenzanthrone in a purity never before obtained. This process passes through intermediates heretofore unknown. I have further found that both the intermediates in this process and 6-Bz-l-diaminobenzanthrone produce azo dyes of unexpected shades and especially unexpectedly deep shades. w 1-- In the practice of my invention a Bz-l-halogeno-G nitrobenzanthrone is reacted in an inert solvent in the presence of a catalyst and an acid binding agent above 150 C. with an arylsulfonamide to form a Bz-l-arylsulfonamido-6-nitrobenzanthrone. This is then reduced to the corresponding Bz-1-arylsulfonamido-6-aminobenzanthrone which in turn is hydrolyzed to give a very pure 6-Bz-l-diaminobenzanthrone. The preparation can be illustrated by the following equation:

The starting material for the process of my invention,

Bz-l-bromo-6-nitrobenzanthrone, is obtained from benzanthrone by monobromination, followed by mononitraphenyl-4-sulfonamide, anisolesulfonamide, nitrobenzene sulfonamide, and the like. The nature of the aryl group in the sulfonamide used is not critical except that it Paiented Jan. 28, 1958 should be cheap and readily available and be free of interfering groups such as halogen and amino.

This reaction is carried out in a high boiling inert solvent, of which nitrobenzene is the preferred example, and in the presence of a catalyst such as finely divided copper or copper salts, and also in the presence of an acid binding agent such as an alkali metal or ammonium acetate or an alkali metal or ammonium carbonate. The sulfonamidation will take place at temperatures ranging from ISO-215 C. although a preferred range is -180" C.- The product, a Bz-l-arylsulfonamido-6-nitrobenzanthrone, is isolated by filtration from the cooled reaction mixture.

Bz-l-arylsulfonamido-6-nitrobenzanthrones form alkali salts soluble in water. This is an added advantage in our process, since it permits a further purification by dissolving in alkaline solution, clarifying and reprecipitating with acid, if such is desired. It is also an advantage of this process of my invention that the Bz-l-arylsulfonamido-6-nitrobenzanthrone can be reduced under mild conditions such as in aqueous alkaline solution. The reduction can be carried out by warming with an alkali metal ammonium sulfide such as sodium sulfide or bydrosulfide, potassium sulfide, ammonium sulfide and the like. Alternatively it can be carried out by warming with dilute caustic and sodium hydrosulte. This latter is epsecially advantageous because it can be combined with an alkali purification of the nitrosulfonamidobenzanthrone, if desired. It is usually necessary to heat the reaction mixture above 35 C. to obtain reduction and slightly higher temperatures are preferred. Too high a temperature, however, may cause saponification.

Reduction can also be carried out catalytically with hydrogen and a hydrogenation catalyst or under acid conditions by using metals and aqueous acids. The resulting Bz-1-arylsulfonamido-6-aminobenzanthrones can be used to obtain azo dyes of very interesting shades which are usable in themselves. The remaining hydrogen on the sulfonamido group may be also replaced by alkyl, acyl, and other groups to produce additional new azo dyes.

In the process of my invention, the saponification of the Bz-l-arylsulfonamido 6 aminobenzanthrone takes place readily at ordinary temperatures on contact with strong acids such as concentrated sulfuric acid. The product is isolated by dilution with water to form a very high quality 6-Bz-l-diaminobenzanthrone.

6-Bz-l-diaminobenzanthrone has been reported to have been prepared by methods such as dinitration and reduction. This method gives a product of very low purity since this reaction sequence produces isomeric materials from which the desired isomer has never been separated completely pure. Prior literature gives melting points of 225-230 C. .The product of our invention when observed under a microscope is found to melt at a much higher temperature. At 240-245 C. the material is observed to grow into long needles which do not melt until a temperature of 259-263 C. is reached. This large increase in the melting point is indicative of a very large improvement in the state of purity. It has not heretofore been recognized by the art that it is possible to make a diaminobenzanthrone of this purity. This degree of purity is possible principally because the process of my invention proceeds by a route which does not give isomer, such as gave trouble in prior art routes.

Either 6-Bz-l-diaminobenzanthrone or Bz-l-arylsulfonamido-6-aminobenzanthrone can be diazotized and coupled with azo coupling components togive colors ranging over most of the spectrum. Coupling components which may be used are acetoacetanilide, para-cresol, 3-

methyl-S-pyrazolone, benzoylacetonitrile, salicylic acid,

Jags-1 35.88

and coupling it to one couplingcomponent. Hydrolysis of.

the arylsulfonamido group with acid, followed by diazo-. tization of the newly ,formedfree amino group permit 'HOs'S coupling into a second and difierent coupling component. The monoazo dyes-formed from the arylsulfonamidoaminobenzanthrone 'are themselves interesting and valuable dyestuffs. Where such coupling components contain metallizable groups such as an ortho-hydroxycarboxylic acid residue, the dyes so obtainedrnay be, metallized either in substance or on the fiber. It is also possible to prepare polyazo dyes by successive couplings, in which atleast one of the-azo groups is flanked by bydroXY, carboxy, or -methoxy groups situated in .both ortho positions, which dyes'may be converted to metallic complexes. Such dyes are distinguished by their .exceilent light-fastness.

It is an advantage of the dyes from diaminobenzanthrone that one'obtains disazo dyes having deep shades which are difficult to obtain. These deep shades are most unexpected because structurally 6-Bz-1-diaminobenzanthrone is a 2,3,2-substituted benzidine ascan'be seen by the following formula in which the darker lines outline thebenzidinestructure.

Azbenzidine substituted in? this manner is expectedto give disazodyeswvhichare not as deep in shade as thecorresponding f benzidine. dyes, rather thandeeper -as -has been found:.to he1.-the 1case- An example of'this can-be shown byccmparisonof .thezcoupling of 6 -Bz-l-diaminobenzanthroneto cresotinic: :acid;-with the. corresponding dye-=-frm benzidineuand ;cresotinic acid '(C. I. 411-).

1100.0 N=NOON=N .0001:

no on HI CH3 his most unexpected to find that thedye .from the diaminobenzanthrone is a'brownwith a shade similar to Color-Index-601 and'not at-allclose to*the yellow of the corresponding benzidine dye. The -brown of 'Colorllndex 601 is a 'trisazo'dye and nota'disazo dye. Ibis-minus- ,4. tr iv of he van ag hat d ep sh es are obtain ble with disazo dyes, shades which heretofore have required much more complicated trisazo dyes. It is a further advantage of the dyes that the shades are superior in lightfastness to the analogous benzidine dyestuffs. This is a property in which the-benzidine dyestuflfs have been notoriously. lacking and it. is mostuuneXpected-to find the corresponding diaminobenzanthrone dyestuifs to be good in'thisrespect.

"The comparison-of dyes from diaminobenzanthrone with benzidine dyes is also striking when the coupling component is an aminonaphthol ..sulfonic acid. The

couplings v;cv.f benzidine and its. derivatives with such compounds gives blues. Forexam-ple, tetrazotized benzidine when coupled to.1-amino=81naphthol 3,61disulfonic acid gives an important direct blue dye for cotton, Direct Blue 2B (C. I. 406), of the structure Itis thereforevery-surprising that diaminobenzanthrone,

a'2','3,2-substituted benzidine, when coupled to l-amino- '8-naphthol 3,6-disulfonic acid gives 'a very much greener shade, far removed from the shade of Direct Blue 2B. Their deep shades make the dyes from diamino-benzanthrone-coupled to aminonaphthol sulfonic acids a prechoice-of such salts is not'critical and the dyestufis of my invention are shown in the form of the free acid.

The-pure diaminobenzanthrone of my invention is also suitable as a starting material for the preparation of vat dyes, as is also the intermediate arylsulfonamido amino benzanthrone. Since these compounds are purer than the previously known diaminobenzanthrone, the vat dyes ob- .tained by suchreactions as condensation with halogenoanthraquinones and the like are also purer and the resulting shades :are brighter.

My invention can be illustrated by the following examples in which parts are by weight, unless otherwise Example 1 A mixture .of v17.7 ,parts pfBzda-bromo-Gmitrobenzanthronetprepared according to Dex/.1. Chem. Soc. .1940, 1474),, .1210 parts ofstoluenesulfonamide, 6.9 parts of .anhydrous potassium acetate, 2 parts ;of,copper butyl- Phthalateand ;3..0.0. .parts -of nitrobenzene is heated at until he reac ion .is substantially complete.

cooleditci6.0.1.C..andfi1tered. The crude Bzalrtolylaminw ni r heuzanthrone thus .cbtainedis. dissolved inxsodium ihydrox't'de .sclution clarified thy .vfiltration .and tepqrecipi I tatetlpwith fiiluteaeetteacid. Thcgpure gprc uct, when dry, melts about 288-942. with decomposition.

Example 2 tinsel-Gem A solution of 8.89 parts of dry Bz-l-tolylsulfonamido- 6-nitrobenzanthrone, obtained according to Example 1, in a mixture consisting of 71 parts of 17% sodium hydroxide solution, 350 parts of water and 17.1 parts of sodium hydrosulfite is warmed at 50-55" C. until the reduction is complete. The product is precipitated as the sodium salt by the addition of sodium chloride, and isolated by filtration. The salt is converted to the free acid form by dissolving in 350 parts of water and precipitating with acetic acid, filtering and drying.

Alternatively, the reduction can be carried out by modifying the above procedure in the following manner. The Bz-1-tolylsulfonamido-6-nitrobenzanthrone is warmed with the water and the sodium hydroxide. The solution thus formed is clarified by filtration and the sodium hydrosulfite is added. The product is isolated and acidified as before.

Example 3 Saponification of the tolylsulfonamido group is accomplished by mixing 4.14 parts of Bz-l-tolylsulfonamido-6- aminobenzanthrone, prepared as in Example 2 with 74 parts of 97% sulfuric acid and allowing the mixture to remain at room temperature until saponification is complete. The product is isolated by drowning in 300 parts of water, filtering, slurrying in sodium hydroxide solution which gives the free diamine, filtering, washing with Water, and drying. The 6-Bz-1-diaminobenzanthrone thus pro duced is of excellent quality. On the hot stage of a polarizing microscope, this product is observed to grow into needles over the range 240245 C. and to melt at 259-263" C.

Example 4 CHI NHSm-ON CHI Example 6 NgH l 0 Saponification of 4.24 parts of the product obtained in Example 5 using the procedure of Example 3, results in -Bz-l-diaminobenzanthrone of good quality.

Example 7 The disazo dye of 6-Bz-l-diaminobenzanthrone coupled to cresotinie acid is prepared as follows:

To a partial solution of 2.60 parts of 6-Bz-1-diaminobenzanthrone in 52.5 parts cold glacial acetic acid is added a solution of 1.44 parts sodium nitrite in 18.4 parts of 97% sulfuric acid. The resultant solution is diluted with 71 parts ether and the precipitated tetrazo washed with ether.

The entire amount of tetrazo product is dissolved in 60 parts water and the resultant solution added to a cold solution made by dissolving 3.8 parts of 2-hydroxy-3- methyl-benzoic acid in a solution in turn made by adding 10.0 parts sodium carbonate to parts by volume of water and cooling. The resultant slurry of disazo dye is stirred until all of the tetrazo has been coupled. It is then heated for several hours at moderate temperatures, isolated by filtration and dried.

The disazo dye when dyed on animal and vegetable fibers gives a brown shade similar to the brown of Color Index 601 and behaves similarly on after-treatment with bichromate-copper sulfateacetic acid, turning to a redder brown. However, our disazo dye is greatly superior in fastness to light to the dye of Color Index 601.

Example 8 Other disazo dyes from 6-Bz-l-diaminobenzanthrone, prepared using the method of Example 7 are listed below according to the coupling component used.

Coupling Component used Shade of Dlsazo Dye obtained on cotton 1-amlno-8-naphthol-3,6-dlsulfonio A igl ue much greener than C. I. Z-amirio-S-naphthol-6-sultonic acid...

A navy somewhat redder than C. I. 401. When diazotized and developed with m-toluylone diamine it behaved similarly. B-angRm-t-naphtho1-5,7-dlsuli'onlc A greenish blue.

Example 9 The fi-Bz-l-diaminobenzanthrone was used as a fast base with-conplingcon pon h s of'rthelfiephthol yn for the pr uction ofideep shadeseneotton ,lhe -iQ11ow-. ili sh ws th ,results obtained when itetrazotized 6-. I B'z--1=diaminobenzan th rone is L'brought ZfinIQ. .Cnntaet with cotton cloth padded with the following compounds: 1-(2',3-hydroxynaphthoylamido)- naphthaleneuu r... Ablue. 1-(2',3-hydroxynaphthoylamido)- 2,5-dimethoxybenzene- Ablue. 1 (2',3' hydroxydibenzofuranyl- 3-nitrobenzene ,A blue greener :than above.

3,3 dimethyl 4,4'-diaeetoa cetylamido-biphenyl A dark copper-brown. 1 -i=( 23. ahvdroxyan hrylcarbonyl amide) -benzene. a, ,.n...a.,t.Atgreyislrr.bln eneen l (3,2 hydroxycarhazolylcarbonylamido)-4-chlorobenzene A dark violet brown. 1 (2',3 hydroxydibenzofuranyl carbonylamido) 2,5-dimethoxybenzene--- A dark violet brown. 2,[2' --hydroxy-,3=(1l-benzo|a]carbazolyl) carbonylamido12-methyl- 4-methoxy-benzene r A dark green grey.

{ExamplelO The Bz-l-tolylsulfonamido-6raminobenzanthrone was used as a fast base with eoupling components gf the Napthol AS type. The following list shows the results obtained when diazotized ,Bz-l-tolylsulf onamido-6 amir19- benzanth'rone is 'broughtinto 'contact with-cotton Cloth padded with the followingcornpounds:

1-(233Ehydroxynaphthoylatnido) 4-ch1or r 1 henzene,"We"-subway-E-" uted; (21,3 -11ydroxynaphthoylami o) -2-me hyle benzene",as-wetness-M, mv tAthluered.

l (2',3' hydroxynaphthoylamido)-2-methoxvbe e a. i- Azbhiere 1 4233 -hydnoxynaphthqylamide) 7131mm be ze e v Abluereda- 1- (233 -hydroaynephthqylamidq)enaphthel- V emcee,Faun-m-uflqumvsv Abluemd is 1 (2', 3-hydroxynaphthoylamido)-2-ethoxy- I p A blue red.

bem'ene V p This application-is a division of my co-pending appli- 1 cation, Serial No. 449,267, filed August 11, 1954.

Iclaim:

1. The process for preparing a substantially pure 6-Bzl-diaminobenzanthrone which comprises heating Bz-lbromo-6-nitrobenzanthrone in an inert solvent with an arylsulfonamide in which the aryl group is a carbocyclic radical ofdesxthamthreeuzing-s until thBLbITQIDO group, is substantially; replaced-by an arylsul-ionamido @group, re-

ducing-the resulting B2:laarylsulfonamidWn-itrobenzanthrone ,to the corresponding 6 -amino compound, vand treating the wresulting :sulfonamidoraminorbenza-nthrone with 3;StI'DX} g a$id;11:0 obtain.6-Bz-l diaminobenzanthrone.

2. The pnocess-oftclaim -:1 in rwhich thezneduction-is carrieduoiubby heatingpthe nit-roacornpoundtawith an alkaline reducing-agent-selected iromtthe groupconsisting vof alkali sulfides and hydrosulfites.

3. The, processwfielai-mJ- intwhich' the rarylsulfonamide is a .monocycliearylsulionamide;

'4. The process: oflclaim-S-in which the arylsulfonamide istoluenesulfonamide.

5. :Atprocess pf skint-a4 in which "the- 3211710111635- ulfonamidoenitrobenzanthrone is P ified y dissolution into aqueous alkali and removal of impuritiesby filtration, and the purified material in the filtrate is reduced with sodium hydrosnlfite.

6. Bz-l-arylsulfonamido 6-nitrobenzanthrones in which the aryl group is a carbocyclic radical of less than three llHgS.

7. Bz-1-tolylsulfonamide-6-uitrolsenzanthrone.

References Cited in the file ;c f th;is patent omenrnnrnneuces- 'Beilsteins Handbook, "4th edition, vol. 114, '2nd'Suppl. 195l,pp. 76-77. 

1. THE PROCESS FOR PREPARING A SUBSTANTIALLY PURE 6-BZ1-DIAMINOBENZANTHRONE WHICH COMPRISES HEATING BZ-1BROMO-6-NITROBENZANTHRONE IN AN INERT SOLVENT WITH AN ARYLSULFONAMIDE IN WHICH THE ARYL GROUP IS A CARBOCYCLIC RADICAL OF LESS THAN THREE RINGS UNTIL THE BROMO GROUP IS SUBSTANTIALLY REPLACED BY AN ARYLSULFONAMIDO GROUP, REDUCING THE RESULTING BZ-1-ARYLSULFONAMIDO-6-NITROBENZANTHRONE TO THE CORRESPONDING 6-AMINO COMPOUND, AND TREATING THE RESULTING SULFONAMIDO-AMINO-BENZANTHRONE WITH A STRONG ACID TO OBTAIN 6-BZ-1-DIAMINOBENZANTHRONE. 